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E. '0; GOORDMAN.

'SELF GRIPPING MANDREL. APPLICATION FILED AUfi.3, 1921.

Reissued June 20, 1922.

gnventoz UNITED STATES PATENT OFFICE.

ELMER O. GOORDMAN, 0F NORGE, VIRGINIA, ASSIGNOR TO THE EFFICIENCY vMACHINE TOOL PRODUCTS CO., OF BRIDGEPORT, CONNECTICUT, A CORPORA- TIONor CONNECTICUT.

SELF-GRIFFING MANDREL. I

The invention has for its objects to pro vide an improved mandrel ofthis character having means for automatically gripping o r forming adriving connection with the work, and preferably also with thelathechuck or other driving element of the machi.ne;. to'

provide gripping means which will also operate automatically to centerthe mandrel in the machine, or to center the work on the mandrel, orboth, withreliability and accuracy; to provide gripping meanswhich willpermit the application of the work to the mandrel, the insertion of themandrel in the machine, or the removal of either mandrel or work by asimple and direct operation without the use of tools; and to providegripping means which is of such a nature as readily to adapt the samemandrel to use with pieces of work of widely differing internaldiameters.

The foregoing and other objects of the invention, together with meanswhereby the same may be carried into effect, will best be understoodfrom the following descrip tion of one form or embodiment thereofillustrated in the accompanying drawings, in which:

Figure 1 is a perspective view of a portion of a lathe having a piece ofwork sup ported therein by means of a mandrel constructed in accordancewith the invention, said mandrel being operatively connected with thedriving element of the lathe by means of a chuck of familiar form.

Fi 2 is a similar view showing the man rel driven by the usual lathedog.

Fig. 3 is an enlarged perspective view of the mandrel per se.

Fig. 4 is an elevation, partly broken away, of the mandrel, showing oneof the gripping 'cured in place by set screws 23.

Specification of Reissued Letters Patent. Reissued J 20 1922 Originalno. 1,323,855fdated December 2, 1919, Serial No. 301,466, filed June a,1919.

- reissue filed August 3, 1921.

Application for Serial No. 489,634.

rollers and one of the retaining caps or collars removed.

Figs. 5 and 6 are enlarged sections on the l nes 55 and 6-6respectively, Fig. 4.

Fig. 7 is a view illustrating, in transverse section, a series ofinterchangeable sleeves employed to adapt the mandrel for use inconnection with work of different internal facilitate their connectionwith lathe dogs of the usual type.

The mandrel body 10 is provided with a plurality of grooves 17,preferably three in number, spaced at equal intervals about said bodyand extending substantially throughout the length thereof, said groovespassing under and being bridged by the collar 11. Located in theportions of the grooves 17 which are formed in the driving portion 13 ofthe mandrelare gripping rollers 18, while similarly located in theportions of said grooves which are formedin the driven portion 12 of themandrel are similar gripping rollers 19 They gripping rollers 18 and 19are formed with reduced inner ends 20 which are engaged beneath thecollar 11,

drel and into engagement with the ends of the body portion 10 thereof,and being se- Enga ement of the collar 11 and caps 22 with t e reducedend portions 20 and 21 of the rollers 18 and 19 serves to retain saidrollers in position in they grooves 17 removal of said caps 22permitting the disengagement of the ends 20 of the rollers from thecollar 11 and the consequent removal of said rollers from the mandrel,as illustrated at the right in Fig. 4.

The grooves 17 are preferably substantially rectangular in -cr ossse'ctioin'being' of equalqdepth at both sides, and as rollers 18 and, 19therein constituteintermittent on one way gripping devices foroperatlvely.

connecting the mandrel body with a surrounding" cylindrical member forrotation in unison therewith. in one direction or the other, dependingupon the position. of said rollers at one side, orthe other'yof saidgames The rollers 18 and 19 are normally held. at oppositesides,respectlvely, of the grooves .17- by springs2 1 located in said grooves,each of sa1d sprlng's being preferably continuousthroughout the lengthof the corresponding groove, and each having a portion coop ating withv'll(j)ll6l 18 therein and a connectedportion 26 coo rating with thecorresponding roller 19, sald portions 25 and 26 being bowedxin oppositedirections to hold said rollers in engagement with the opposite sides 5of said slots, as

above explained.

As will now be apparent by reference to Figs. Sand 6, the grippingrollers, 18 and 1 19 are oppositelyacting, theirollers 19being' adaptedtotransmit rotary motion n one 1 direction from an outside source to the'Hdriven portion 12 of themandrel, and the the drivenportion 12 ofthemandrel may be roller-s18 being adapted to transmit rotary,motioi'rinthe same directionfrom't edriving portion oli the mandrel tocylindrlcal mcn'iber placed thereon. For

ample, assuming that the work is to be; rotated 1n.:a counter-clockwisetdlrectlon as Tindicated by the arrows on Figs fi and 6 (this being thenormaldirection ot rotation in the operation. of the ordinary .jlathe,as

indicated by the arrows. on Figs. 1 and. 2),

inserted ,into a suitable lathe chuck 27 (Fig.1) of any, suitable formbut of an internal diameter substantially fitting the mandrel body,whereupon .it. will be seen that rotary motion of said chuck in i acounter-clockwise direction will be; transmitted to the mandrel throughthe rollers, 19.. lfipprioito the insertion of themandrel into thechnclntheie be applied to; the drivwrotary ingend 13 thereof piece ofhollow work 28 (Fig having an internal bore substanall ,tting the inEtl'lflllfl'lj, it will beseen that movement of sa .1 mandrel inf acounterj-clocl cwise direction will be transmittec though the rollers 18to said work.

It will be seen that the. mandrelymay be read ly :plaeed. inner removedfrom 1 the .chuck, ndufthe :work applied to, or, removed from themat c.'61, by a simple operation ,not

the use of tools that is to say, by tl ve. 'ltm itudinal. ,or' axial:movei; the par s accompanied, if necesis; transmitt purpose of asingthe gripping devices;

yualSlight an ilar movei nent in the 1011 opposite to that n whichpower.

" letween said parts, forthe I 1 If desired, and as shown in Fig. 2, themandrel above described may be operatively connected with the lathe bymeans of the usual lathe dog 29 instead of by means of the chuck 27, inwhich case said lathe dog may be passed over the-reduced terminal 14 atthe driven end of the mandrel, the dog set screw 30 being engaged withthe corre-v sponding flattenedportion 16, and the head center 31 of thelathe being engaged with thesocket It will be understood that in eithercase, the tailcenter 32 ofthe lathe will be engaged with; the socket 15at the driving endofthe mandrel.

From the foregoing it wil be seen that the work on the drivinghend ofthe mandrel is rotated bysaid mandrel thronghrengagement ofthe rollers18 with the interior of thework, so-that, as thus far explained, theinterior diameter of said work must 1 appi I the n'iandrel body 10, Inaccordance wlth an important object oithe invention, pro- I vision ismade for adapting the same1nandrel to use with different pieces ofworkof different internal diameters. To; this end there may be -prov1ded aser es of 1nterchangeable:sleeves 33 (see F 1g. 7) each of an internaldiameter eorresponding to-the external diameter of the mandel body butdifi erlng in thickness, and consequently, in external diameter,throughout the series,

said sleeves being each rendered eXpa'nsible' by loi'lgitudinal slot 34.and,in the case of the thicker sleeves of the series, by

:nlditional weakening grooves, 35. .These sleeves may, ,oflcourse, be ofanyode sired number, four beingfshown way of illustration, and may.differ in thickness byan y desired an'iount. In applying tothe mandrel apiece-of work of an internal diameter imately equal the exteriordiameter (of materially greater than the external dis .ameter ot themandrel body, there is disposed between said workand the mandrel bodythat sleeve of the Series which most.

closely approximates in external, diameter the n'iternal diameteryof thework. When,

there'fcn-e, the mandrel is rotated,the rollers 18, l'aearing outwardlyagainst the -;1nter or of the sleeve33' which surrounds them,w1ll

tend to expand. said sleeve and force. the same Into close; engagement,with the 1nterior oithe work, as; to provide a driving fit. p Thereweakening grooves arenemi loyed, said grooves are. preferably disposedabout each sleeve at, substantially, equal? dista ,s from each othergandfrom the correspmiding. slot 34. :Alsmyas shown in the, case er the slot34 in Fig. 3, saidigroovesmand slots are preferably ofslightly'helicaljform in order that the work. may be engaged by i thesleeve throughout a complete circle...

ngroll skin eacl'i series series being at least 7 en that hythepleasano'f three in number), said rollers will serve, not only as adriving connection between the chuck and the mandrel and between themandrel and the work, but, by reason of the equal outward thrust of allof the rollers in each series,said rollers will serve also accurately tocenter the mandrel in the chuck and as accurately to center the work onthe mandrel, so that it has been found in practice that, by the use of amandrel of the character described, cylindrical bodies having relativelythin walls may be turned with greater accuracy than by any meansheretofore in use.

Having thus described my invention, I claim:

1. A work-holding mandrel having driven and driving portions, saidportions being provided with means for automatically forming drivingconnections respectively with a machine driving element and with a pieceof work to be driven.

2. A work-holding mandrel having driven and driving portions providedrespectively with opposltely acting automatic gripping members.

3. A work-holding mandrel having driven and driving portions providedwith longitudinal grooves, rollers in said grooves, and springs forforcing the rollers of the driven and driving portions respectivel intoengagement with opposite sides of their respective grooves.

4. A work-holding mandrel having driven and driving portions and havinga continu ous longitudinal groove common to both of said portions, andoppositely acting automatic gripping members located respectively in theportions of said groove formed in the several portions of said member.

5. A work-holding mandrel having driven and driving portions and havinga continuous longitudinal groove common to both of said portions and ofequal depth at both sides, rollers located respectively in the portionsof said groove formed in the several portions of said member, andsprings for forcing said rollers respectively into engagement withopposite. sides of their respective grooi e portions.

6. A work-holding mandrel having driven and driving portions, a collarbetween said portions, and a continuous longitudinal groove common toboth of said portions and extending under said collar, and oppositelyacting automatic gripping rollers located respectively in the portionsof said groove formed in the several portions of said member and havingend portions engaged by said collar to retain said rollers in place.

7 A work-holding mandrel having driven and driving portions and acontinuous longitudinal groove common to both of said portions, rollerslocated respectively in the portions of said groove formed in theseveral portions of said member, and a continu ous spring in said groovehaving portions for forcing said rollers respectively into engagementwith opposite sides of their respective groove portions.

8. A work-holding mandrel having driven and driving ortions providedwith means for formin riving connections respectively with a mac inedriving member and with a piece of work to be driven, said means beingadapted also to center said mandrel in said driving member and to centersaid work on said mandrel.

9. A work-holding mandrel having driven and driving portions providedwith rectangular longitudinal grooves, rollers in said grooves, andsprings for forcing the rollers of the driven and driving portions,respectively, into'engagement with opposite sides of their respectivegrooves.

10. A work holding mandrel having in combination a mandrel body adaptedto be inserted in hollow work and to be rotated in a predetermineddirection to drive the work, a surface carried by said body and inclinedoutwardly from its forward to its rearward side, a work gripping rollercarried by said body and arranged to engage said surface and means foryieldinglv forcing said roller relatively to said surface in a'direction re verse to the operative direction of rotation of the mandrelbody to grip the work.

11. A work holding mandrel having in combination a mandrel bodyconstructed for insertion in hollow work and arranged to be rotated in apredetermined direction to drive work mounted thereon, a series ofinclined surfaces carried by said body and substan tially equally spacedabout said body, a series of work gripping rollers arranged respectivelyto engage said surfaces and individual actuating springs for each rollertending to force said rollers in a direction relatively to said surfacesreverse to the work driving direction of rotation of said body to gripthe work.

12. A work holding mandrel having in combination a mandrel body adaptedto be inserted in hollow work and to be rotated in a predetermineddirection to drive the work, a groove formed in said body having aninner face inclined outwardly from the forward to the rearward side ofthe groove, a work gripping roller mounted in the groove and a springmounted in the groove behind the roller and arranged to force the rollerrelatively to said groove in a direction reverse to the operativedirection of rotation of the mandrel body to grip the work.

13. A work gripping mandrel having in combination a mandrel body, agroove formed in said body, a work gripping roller mounted in the grooveand a leaf spring mounted in the groove behind the roller and arrangedto force the roller in a directioii re letiv ely to said groove to gripthe Work and means secured to the body v and extending ,over the outerend of the spriiig for h'olding thespring inplacein the; groove.

eombinat1o11 a I mandrel body, a; groove.

14 A work gripping "niendrethaving in combinationa niandrel bod ,nadapted to be inserted in hollow Work and; tote-rotated s in a,predetermined direction: to drive-the Work, it groowfe formed insaidbody'hawng groove and a bent leaf spring inountetlQin.

"direction reverse to the operative direction F2 place with relation tothe mandrel body. 16: A WOTk 'holding mandrel having in an inner wallinclined outwerdly frointhe forward to the rearward sideofthe groove,

a w'vorkzgripping roller mounted in the the gwm 'e behind the" rolleiand arranged to foree the' roller relatively to the groove in a of rotation'of the mdndrel hodyto grip the A worl o holding mandrel incombination a mandrel body, an inclined ping roller carried said body"and erra'nged to engage said surface, means secured to thefhody "andextendingover: the-outer ends of the roller for holding the roller incombination a "mandrel wbody, a groove formed "in said body, a 5 ivlofkgripping roller a #17: A: Work holding mandrel having in formed insaidbody a work gripping roller mounted in the groove, a leaf sprlngmountrzinged to foree'the roller relatively to the ,ed in the groovebehindthe roller and ar- 40 groove inkzm direction to" grip the ork, and

thenroller and springin position in the groove. i

I 18. UAwork grlpp'ing niandi'el having in combination a mandrel body, asenes'of grooves "fornie'd, in said body. a work gripping roller mountedin each of said grooves, 1a=1e2ifspring mounted ineaoh of said grooves"behind the corresponding roller and arsurface cari'ied bjy said body,"it Work grip-1 capsmonnted on the manidrel'hody and ex? tending over theends of the springsend rollers tonholdthe semeid'position in thegrooves.

Signed at Notgmin the county of J ames' (lity and-State of Virginia;this 8th day'oi' Julygl92l v I I r r 1 mounted in the groove iand meansfor hold- I i ing a 'roiler in the groove comprising a; re-

t o; GQ 'RIDMAN;

means carried byv saidfbody and extending over the ends of the rollerand spring to hold

